Abstract: Munitions are encountered in a variety of underwater environments as unexploded ordnance (UXO) or munitions and explosives of concern (MEC). These items can cause unacceptable explosive risks to critical infrastructure, recreational divers, and fishermen. The primary goal of the demonstrations was to validate an underwater suite of tools that can be used to render underwater UXO and MEC safe in shallow water (i.e., up to 100 ft). US Navy underwater ranges in the Gulf of Mexico, south of the Naval Support Activity–Panama City, were selected for the first two demonstrations to fully display the integrated system by processing inert munitions, such as the Navy 5 in./38 cal and the Army 105 mm High Explosive (HE) M1 projectile. The third demonstration, however, occurred at the Naval Surface Warfare Center (NSWC), Crane, Lake Glendora Test Facility, in Sullivan, Indiana. Twenty US Army 105 mm HE M1 projectiles filled with TNT were successfully processed. Overall, this project showed that Gradient Technology’s high-pressure waterjet demilitarization technology can be reliably operated underwater at depths less than 100 ft of seawater when the supporting equipment is located on the deck of a vessel or floating pier system.